Recorder for musical dynamics



Jan. 18, 1927.

- J. HQFMANN RECORDER FOR MUSICAL DYNAMIC;

Filed New 5, 1925 2 Sheets-Sheet 1 Jan. 18 1927.

i J. HOFMANN RECORDER FOR MUSICAL DYNAMICS Filed May 5. 1925 2Sheetg-Sheet 2 Patented Jan. 18, 1927.

UNITED STATES PATENT OFFICE.

JOSE! HOFMANN, OF BAUMABQCHE, WI ERLAND.

RECORDER FOR MUSICAL DYNAMICS.

Application filed May 5, 1925, Serial No. 28,158, and in Great B1 itainMay 26, 1924.

This invention relates to recording devices for producing master musicrecords in keyoperated master musical instruments, such as recordingpianos and the like, and has for its object to provide a device forrecording the vactual pianistic touch on music records automaticallyduring their production.

Tonal effects (dynamics) as produced by artistic player pianos arecontrolled by specially arranged perforations on the rightand left sideof the music record usually consisting of a perforated roll of paper.

In the known recording systems, usually these perforations are notapplied to the master or initialrecord by the recording artist himself,but are either recorded with the aid of a Separate contrivancemanipulated by another person listening to the artist during therecording period and applying the dynamics according to his ownjudgment, or they are added afterwards. The actual touch of thelccording pianist has there fore no effect upon the dynamic indicationsof the recording ,machine and consequently the finished master record orroll from which the duplicates are made for the player piano lacks theindividuality of the producin artist.

,1 0W acc rdin to this invention, the pianist is enable by an automaticmechanism to record his .own dynamics without interference by others bymeans of a device which is highly sensitive to the various degreesof theblow or blows as delivered by his fingers, hands or arms. Each blow andits exact dynamic degree is transformed into corresponding recordperforations or marks on the roll of paper and a roll thus made whenused with a reproducing player piano will therefore bring about orindicatea tonal picture identical to "the pianists original effort.

To this .end the in ention consists in a device which is so associatedwith the keyboard of the recording key-operated musical instrument as toutilize the dynamic force imparted by the player individually to eachkey or to a number of keys of the keyboard to actuate mechanism adaptedautomatically to control in a correspondingly suitable manner the meansemployed for effecting the dynamic perforation or marking of the recordwhich is subsequently used to control the tonal expression of thereproducing instrument. Inthis device the transmission and translationis by preference of a mechanical kind and the operation of the actualperforating or marking mechanism is with advantage electro-magnetical.

Recording as well as reproducing player pianos are, as a rule, dividedinto right and left dynamics; in other words, one half of the keyboardis dynamically controlled by perforations on the right hand side of theroll of paper, and the other half by perforations on the left hand side.

Accordingly the automatic dynamic device according to this invention ispreferably also divided into two, or rather, arranged in duplicate, onedevice being allotted to each half of the piano in order to enable righthand dynamics to be marked independently from left hand dynamics.

The instrumentalities that actually form the record in the music sheetare of well known construction and are not illustrated nor required tobe for an understanding of my invention.

T he accompanying drawings illustrate by way of example a constructionof an automatic dynamic transmission device, embodying the invention andin which like parts are similarly designated.

Fig, 1 is a perspective view of the device arranged at the left handside of the recording piano; and

Fig. 2 an end view thereof.

Fig. 3 is a rear elevation of the control deice, and

Fig. 4 a cross section on the line IV IV of Fig. 3.

Fig. 5 shows in a diagrammatic development, an example of thedisposition of contactsvover the surface of the control drum,

whereby, according to the dynamic force applied to the keys, one or moreof several electric circuits are closed. I

Fig, 6 is a cross-section of the plunger piston,

Below the keyboard A of a master musical instrumentand immediatelyunderneath the white keys B and the black keys C, is pivotally mountedin bearings l a shaft 2 extending in two parts from the middle E-key tothe right and left ends of the key board. Each part of the said shaft 2carries by means of arms 3, rigidly connected thereto at right angles toits axis, a bail or bar 4 located under the forward end of the blackkeys C. Directly above this bar each key B and C has fixed to itsunderside a felt pad 5 acting as a shock absorber when in depressing akey it strikes the bar a. For each half of the key beard therefore theshaft 2, arms 3 and bar 41 foan a rigid rocking frame, for thetransmission of the dynamics of the ri ht and left key boards to theright a hand side of the music sheet. The are normally held in r anshereinafter to be more ll, oescribed, and are caused any one or a numberof I Y? to be rocked the keys or C an extent corresponding to th amountof depression of the key or keys.

At the outer end of each of the said frames, the shaft 2 carries,rigidly secured thereto, a lever arm 6, having fixed to its free end,which is preferably formed as a segment a belt or steel ribbon 'i' theother end of which is secured to a pulley 8 in such manner that when thelever 6 swings upwardly the ribbon causes the pulley 8 to revolveagainst spring action The pulley 8 is fast on a shaft 9 journalledbetween centres 10 which are mounted in standards 11, 11 The shaftcarries fast on it a contactdrum 12 of considerably larger diameter thanthe pulley S in order to obtain an appropriately magnifi d extent of therotary movement on the circumference of the drum 12. Preferably, I donot use a circular pulley but a cam, so that the leverage for theinitial or light impact will be greatest and gradually increase thuscomplementing the successively applied springs 2') and so forth, to bedescribed. Loosely mounted on the shaft 9 in juxtaposition to the drum12 are a series of lingers a, a which normally are held in a fan likeformation (see Fig. 1). The position of each finger is individuallydetermined by arm 0 forming part thereof and adapted under the influenceof springs Z) 6 one allotted and attached to a lug on each of saidfingers to abut against a common stop pin 13 secured par allel with theshaft 9 to the standard 11.

The fingers (1 a extend into the path of rotation of a pin 14 ecuredparallel with the shaft 9 to the face end of the drum 12. The pressureexerted on the oin l l by the lowermostfinger a through the action ofits spring b is calculated to maintain the drum 12 in a neutral againstthe tendency of the weight of the rocking frame, 2, 3, to rotate thedrum in the opposite direction thrt h the lever 6, belt 7 and pulley Tothis end the or balanced. position rocking frame is depressed, the lever6 is caused to swing up through an equal angle and through the steelband or belt 7 rotates the pulley 8 and the drum 12 in the direction ofthe arrow to a correspondin extent. In this rotary movement of the druml2 and according to the erctent thereof, the pin 1 engages in successionthe fingers a a and by swinging them about their fulcrums in oppositionto the action of their springs b v I) causing the latter to offer agradually increasing resistance to the dynamic force exercised throughthe keys on the bar Consequently when the resistance offered by thesprings thus stressed l alances the dynamic force referred to, therotation of the drum is arrested. The dynamic force applied to the keysby the touch of the player thus controls the angle of rotation of thedrum 12 and by suitably arranged contacts on the said drum renders itpossible to effect the closing of electric.

tion on the return movement and at the rcquired speed. If the spring isstrong enough for this, it is not suliiciently sensitive for a lighttouch and for this reason, I use the cam 9 to increase the initialleverage between the frame and drum.

It is evident that, in the event of greater or cun'iulative dynamicforces being applied to the keys when a plurality of the springs Z) Z2becomes operative, the aggregate force of such springs is apt to effecttoo quick a return of the drum to its balanced or neutral position andis thus liable to allow insulficient time for the performance of theoperations of the perforating or marking device. In order tocounteractthis, the piston rod 15 of a dashpot having an inner cylinder16 and an outer cylinder 17 is connected to the pin 1%. On the otherhand, wh n the resistance of the springs in actual use at any one timeis low, itis not necessary to retard the return action of the springs,and to this end in order to regulate the exhaust of such dashpotprogressively in inverse ratio to the extent of the piston stroke thecylinder 16 has formed in its wall an exhaust slot l6 graduallydiminishing in width towards the top of the maximum piston stroke.

The piston 18 is constructed as shown in Fig. 6, and has two ports 19.The piston rod 15 passes loosely through the piston and has rigidlysecured thereto a valve 20 and nut and washer 21. The distance betweenthe valve 20 and washer 21 is slightly greater than the thickness of thepiston so that the ports are open when the piston moves in one directionand are closed by the valve 20 when moving in the opposite direction.

In the example shown the drum 12 in accordance with the extent of itsrotary movcments is adapted to close one or more electric circuits whichactuate electric magnetic devices of known type for automaticallyperforating or marking the perforations for use in controlling thedynamics of a music roll.

In conformity with the adopted system of dynamics in music rolls, theapparatus illustrated in the drawings is assumed to be i used inconnection with instrumentalities which perforate or mark the dynamicsin four rows at each side of the music roll. The perforations in eachrow represent a predetermined force so that perforations of several rowsin alignment represent the aggregate of the forces of the particularrows.

Accordingly the apparatus employed for effecting the closing of theelectric circuits in this case provided with four stationary contactbushes or members al (Z (Z cl adapted to make contact with variouscombinations of insulated contact pieces arranged on the circumferenceof the drum 12. As shown in Fig. 5, the contacts on the drum arearranged in four circumferential rows 6 e 6 e corresponding to the fourpredetermined dynamics of the music roll, so that in the rotation of thedrum in the direction of arrow 1, the contact pieces in the rows makecontact with one or more of the spring contacts d (Z (Z (5* therebyopcrating the perforating or marking devices denoting the aggregatedynamics co responding to the force exercised on the key or keys by theplayers. Normally the spring contact members (Z (Z d are not inconductive contact with the contacts on the drum 12. That is to say,contact al is usually in contact with its contact when the drum is inits Zero position.

Evidently the contacts may be arranged in any suitable manner and on anyother appropriate carrier to meet different requirements of differentsystems of perforating and marking apparatus. Or the rocking frame maybe mounted on knife edge bearings to enhance its sensitiveness and maybe provided with means for adjusting the normal position of the rockingframe if desired. Moreover, the transmission of the movements of thelever 6 to the drum 12 may be effected by means of a toothed segment andpinion and generally speaking, various other structural modificationsmay obviously be made by those skilled in the art without departing fromthe spirit of the invention.

I claim 1. The combination for a key-operated master musical instrument;mechanism associated with and movable by the depression of a key or thedepression of a number of keys thereof accordim to the touch, and

movable in accordance with the touch the same extent with respect to anykey, means to multiply said movement, and devices operated by said meansfor expression rccording instrumentalities.

2. The combination for a key-operated master musical instrument;mechanism as sociated with and movable by the depression of a key or bythe depression of a number of keys thereof according to the touch,

means to multiply said movement, devices operated by said means foroperating expression recording instrumentalities, and means toprogressively add separate resistance to the operation of saidmechanism.

3. The combination for a key-operated master musical instrument;mechanism associated with and movable by the depression of a key or thedepression of a number of keys thereof, according to the touch, means tomultiply said movement, a contact drum rotated by said means, andbrushes contacting with the drum.

4. The combination for a key-operated master musical instrument; abalanced rocking frame associated with a plurality of the :eys thereoffor depression by a key or keys, means to progressively increase theresistance of said frame to movement in accordance with the impact ofthe key.

5. The combination for a key-operated master musical instrument; arocking frame beneath the keys thereof, a drum, means to positivelyconnect said frame and drum to impart partial rotation to the latter,spring means to progressively increase the resistance of said drum torotation, said drum having means thereon for controlling dynamicrecording means.

6. The combination for a key-operated master musical instrument; arocking frame beneath the keys thereof, a drum, means to positivelyconnect said frame and drum to impart partial rotation to the latter,spring means to progressively increase the resistance of said drum torotation, said drum having means thereon for controlling dynamicrecording means, and means to prevent the too rapid rotation of thedrum.

7. The combination for a key-operated master musical instrument; arocking frame, an arm extending from said frame, a drum rotated fromsaid arm, a pin on the drum, and a plurality of spring-retracted fingersprogressively engaged by said pin.

8. The combination for a key-operated master musical instrument; arocking frame, an arm extending from said frame, a drum rotated fromsaid arm, a pin on the drum, a plurality of spring-retracted fingersprogressively engaged by said pin, and means to prevent the too rapidrotation of the drum.

9. The combination for a key-operated master musical instrument; abalanced rocking frame arranged beneath and in the path of movement ofkeys thereof, a rotatable drum operated from said frame, a pinprojecting from an end of the drum, pivoted,

5 spring-retracted lingers successively and angular-1y displaced andarranged to be successively engaged by said pin, and a dashpotto retardthe movement of said drum.

10. The combination for a key-operated master musical instrument; meansassociated with keys thereof to be moved in accordance with the playerstouch, a drum rotated thereby, means to progressively increase theresistance to rotation of said drum and therethrough the resistance ofsaid means to operation, a dash-pot to retard the movement of said drum,and means cooperating with said drum for actuating mechanism for recorddynamics on a music "I sheet.

to return the drum to normal position and means to prevent the too rapidreturn move ment of the drum.

12. The combination for a. he -operated master musical instrument;mechanism associated with and movable by the depression of a key or bythe depression of a number of keys according to the touch, means tomultiply such movement, devices operated by said means for operatingexpression re- 1 cording instrumentalities, and cam means toprogressively increase the resistance to the operation of saidmechanism.

13. The combination for a key-operated master musical instrument; arocking member arranged for actuation by a key or keys of saidinstrument, a spring retracted drum and a variable leverage devicebetween said member and drum.

14. The combination for a key-operated master musical instrument; arocking member arranged for actuation by a key or keys thereof, acontact drum, spring means to increasingly oppose the rotation of saiddrum from its zero position and means between said member and drum, andconnected to both, to vary the operating leverage of said member withrespect to the drum.

15. The combination for a key-operated master-musical instrument,mechanism associated with and movable by the depression of a key or thedepression of a number of keys thereof according to touch, and movablein accordance with the touch the same extent for any key, means tomultiply the movement of said mechanism, devices successively cominginto operation to progressively load said mechanism, and a memberoperated by said means to control recording instrumentalities.

In testimony that I claim the foregoing as my invention, I have signedmy name hereto.

JOSEF HOFMANN.

